If a tree falls ...

Suppose a tree falls in the woods and nobody sees it fall. Has it really fallen?

Or suppose someone does see it fall but they drop dead before they can tell anyone about it.
Or suppose they don't drop dead straight away but they don't bother to tell anyone about it and they die many years later.
Or suppose they write about it in a secret diary which is later destroyed in a fire.
Or suppose the diary is not destroyed, but is never discovered.
Or suppose it is discovered many years later and nobody can decipher the writing.
Or suppose the writing is deciphered and celebrated as a holy text by a whole culture for many generations. But the culture is destroyed by a cataclysmic event which leaves to trace of it ever having existed.

When the Sun becomes a red dwarf and there are no humans left in the universe, will it all amount to nothing?